21012320124 has 72 divisors (see below), whose sum is σ = 53717550432. Its totient is φ = 6924804480.

The previous prime is 21012320117. The next prime is 21012320143. The reversal of 21012320124 is 42102321012.

It is a happy number.

21012320124 is a `hidden beast` number, since 210 + 12 + 320 + 124 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

21012320124 is a modest number, since divided by 320124 gives 21012 as remainder.

It is a junction number, because it is equal to n+sod(n) for n = 21012320097 and 21012320106.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2446702 + ... + 2455274.

Almost surely, 2^21012320124 is an apocalyptic number.

It is an amenable number.

21012320124 is an abundant number, since it is smaller than the sum of its proper divisors (32705230308).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21012320124 is a wasteful number, since it uses less digits than its factorization.

21012320124 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9347 (or 9342 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

Adding to 21012320124 its reverse (42102321012), we get a palindrome (63114641136).

The spelling of 21012320124 in words is "twenty-one billion, twelve million, three hundred twenty thousand, one hundred twenty-four".